The gas breakdown processes in dc microdischarges with a zeolite cathode (ZC) have been investigated. The electric field has a pronounce effect on the electrical characteristics of the ZC. The effects of electric field and secondary emission were discussed in atmospheric plasmas (AP). A nanoporous surface used as micro-reactor could enhance the electron emission from the cathode surface, thus reducing the breakdown voltage (U-B). Results indicate that the UB decreases with increasing ZC diameter and decreasing with gap distance. Microdischarges in spatially confined geometries, such as the nanoporous structure of ZCs, present a promising method for the generation and maintenance of stable AP.